Gas influence on photocurrent generation in metal oxide nanowires

Abstract

Quasi-1D nanostructures of metal-oxide semiconductors, in particular ZnO and SnO2 nanowires, have been extensively investigated for their novel physical properties and are used in many applications such as gas sensors, transparent conducting electrodes, catalysts, solar cells and many other optoelectronic devices. They are n-type semiconductor with a wide band gap, showing a broad visible photoluminescence (PL) emission at room-temperature, depending on gas atmosphere. Moreover, when irradiated with UV-visible radiation (at energy higher than or equal to their band gap), metal oxide nanowires show a great increase of conductance and photocurrent (PC) is generated, if a constant potential is applied. PL emission and PC generation are strongly dependent on surface states and can thus be tuned depending on the surrounding atmosphere. In this work, we studied PC generation in SnO2 nanowires synthesized via evaporation-condensation (EC) process and its dependence on surrounding gas atmosphere, targeting NO2 sensing application. © 2011 Springer Science+Business Media B.V.